1. Field of the Invention
The present invention relates to a head-mounted display controlling method by which a user can see an image by wearing a head-mounted display on his/her head and a head-mounted display system for carrying out the method.
2. Prior Art
In recent years, various systems (head mounted displays and hereafter referred to as HMDs) in which an image display device is mounted to a head of a user and the wearer can see a displayed image throughout his/her field of vision have been proposed and gone into actual use. Such an HMD is an extremely promising system if living space is limited, because it is possible to artificially experience and feel a large screen by the HMD though the HMD is small-sized.
However, in the prior-art HMD, a screen display portion and the user""s eyeballs are fixed with a certain physical position relationship between them and a focal length is constant. As another prior art, there is a technique in which a movement signal is fed back and taken in by an analyzing device and reflected in contents of the screen if the HMD wearer moves his/her head.
However, any of the above pieces of prior art did not give consideration to the following points. In other words, the screen display portion and the eyeballs are fixed with a certain physical position relationship between them in the prior-art system, which causes not only fatigue of wearer""s eyes but also weakens wearer""s eyesight and has a harmful influence on the eyes. In order to avoid this problem, there is proposed an HMD with a structure which is not closed and by which the user can easily see the outside world. However, the user cannot immerse himself/herself in the image and the presence is degraded as compared with a closed HMD.
Although a producer of an image is making a great effort to enhance presence in contents of the image, such an effort merely results in two-dimensional expression (two-dimensional image) and there is a limitation to expression of presence. Therefore, there is proposed three-dimensional images made by utilizing an optical illusion. However, watching today""s three-dimensional image causes more fatigue than watching the two-dimensional image and some percentage of audiences cannot see a video as a two-dimensional one in reality.
In another prior-art system, a movement signal is fed back to contents of an image when the wearer moves his/her head. This is suitable as means for moving in virtual space according to calculation by a computer and has flexible unfolding in which videos are created at any time by calculation. However, this is not compatible with conventional video contents (e.g., a normal film) that unfold inflexibly as the producer determined.
With the above prior-art problems in view, it is an object of the present invention to provide a head-mounted display system for reducing a harmful influence on a wearer""s eyes, providing enhanced presence, and bringing bidirectional property into contents of inflexible screen unfolding.
To achieve the above object, the first aspect of the controlling method of the present invention is a head-mounted display controlling method for causing a screen display portion provided in a head-mounted display apparatus to move, wherein the screen display portion is moved forward or backward in front of a wearer of the apparatus when an image signal is input to the screen display portion and a predetermined time period has passed.
When a normal film or TV that does not include a control signal is being watched or when business software such as a spreadsheet program is running, by moving the screen display portion forward (or backward) after the predetermined time period has passed as described above, it is possible to prevent the wearer from seeing the image at a constant distance for many hours and to reduce a harmful influence on the wearer""s eyes.
A second aspect of the controlling method of the present invention is a head-mounted display controlling method for causing a screen display portion provided in a head-mounted display apparatus to move based on a control signal output from a video playback device, wherein the screen display portion is selectively moved in any one of directions selected from a lateral direction, a vertical direction, and a diagonal direction that is synthesized by the lateral direction and the vertical direction with keeping a distance between a wearer of the apparatus and the screen display portion at a constant value.
With the second head-mounted display controlling method of the invention, because the screen display portion moves with the distance between the wearer and the screen display portion maintained at a constant value, an intention of the producer of the video software can be reflected. As a result, although the video is two-dimensional, enhanced presence can be reliably provided to the wearer.
A third aspect of the controlling method of the present invention is a head-mounted display controlling method for causing a screen display portion provided in a head-mounted display apparatus to move based on a control signal output from a video playback device, wherein the screen display portion is selectively moved in any one of directions selected from a lateral direction, a vertical direction, and a diagonal direction that is synthesized by the lateral direction and the vertical direction with keeping a distance between a wearer of the apparatus and the screen display portion at a constant value or moved forward or backward in front of the wearer.
With the third head-mounted display controlling method of the invention, not only the screen display portion moves with the distance between the wearer and the screen display portion maintained at a constant value but also the screen display portion moves forward or backward on the straight line between the wearer and the screen display portion. Therefore, a range of movement of the screen display portion can be expanded. As a result, the harmful influence on the eyes can be further reduced and the intention of the producer can be further reflected. As a result, it is possible to provide enhanced presence to the wearer.
A first aspect of the head-mounted display system of the present invention is a head-mounted display system for causing an image signal from a video playback device to be displayed on a screen display portion provided in a head-mounted display apparatus, the head-mounted display system comprising: a driving means for moving the screen display portion forward or backward in front of a wearer of the apparatus; and a control means for controlling so as to move the screen display portion forward or backward by means of the driving means when the image signal is input to the head-mounted display apparatus at every time when a predetermined time period has passed.
A second aspect of the head-mounted display system of the present invention is a head-mounted display system for causing an image signal from a video playback device to be displayed on a screen display portion provided in a head-mounted display apparatus and for causing the screen display portion to move based on a control signal output from the video playback device, the head-mounted display system comprising: a driving means for moving the screen display portion in any one of directions selected from a lateral direction, a vertical direction, and a diagonal direction that is synthesized by the lateral direction and the vertical direction with keeping a distance between a wearer of the apparatus and the screen display portion maintained at a constant value; a detecting means for detecting a movement of the head-mounted display apparatus; and a control means for controlling so as to move the screen display portion by means of the driving means based on a detection signal output from the detecting means and the control signal output from the video playback device.
A third aspect of the head-mounted display system of the present invention is a head-mounted display system for causing an image signal from a video playback device to be displayed on a screen display portion provided in a head-mounted display apparatus and for causing the screen display portion to move based on a control signal output from the video playback device, the head-mounted display system comprising: a driving means for moving the screen display portion in any one of directions selected from a lateral direction, a vertical direction, and a diagonal direction that is synthesized by the lateral direction and the vertical direction with keeping a distance between a wearer of the apparatus and the screen display portion at a constant value and for moving the screen display portion forward or backward in front of the wearer; a detecting means for detecting movement of the head-mounted display apparatus; and a control means for controlling so as to move the screen display portion by means of the driving means based on a detection signal output from the detecting means and the control signal output from the video playback device.
In a fourth aspect of the head-mounted display system of the present invention, the control means has a means to output a feedback signal to the video playback device based on a detection result of the detecting means and to carry out the display of the image based on control signal output from the video playback device.
In a fifth aspect of the head-mounted display system of the present invention, the control means controls a movement of the screen display portion at a predetermined speed.
In a sixth aspect of the head-mounted display system of the present invention, the control means has a means for communicating with the video playback device in a bidirectional based on detection result obtained by the detecting means.